中文摘要：

目的探讨脓毒症大鼠心肌组织内毒素信号转导复合受体．Toll样受体4（TLR4）／髓样分化蛋白．2（MD2）基因表达的变化情况。研究其与心肌组织肿瘤坏死因子-α（TNF-α）基因表达的关系。方法采用腹腔注射5mg／kg体重内毒素（LPS）制作大鼠脓毒症模型。动物分为正常对照组（10只），内毒素注射后1、2、6h组（各10只），利用逆转录-聚合酶链反应（RT-PCR）方法检测心肌组织TLR4／MD2以及TNF-α的基因表达。结果LPS注射后1h，TLR4／MD-2及TNF-α基因表达开始升高，2h达高峰，6h逐渐下降，各时间点的表达均显著高于对照组（P〈0．01）。相关分析表明，心肌TUM／MD2基因表达分别与TNF-α基因表达呈显著正相关（P〈0．05）。结论LPS可上调心肌组织TLR4／MD-2基因表达并诱导早期炎症细胞因子TNF-α基因表达。TLR4识别LPS信号是以TLR4／MD-2复合受体的形式完成的。而且在识别过程中，MD-2是TLR4必需的作用分子。

英文摘要：

Objective To investigate the change of Toll-like receptor 4 （TLR4） and myeloid differential protein-2 （MD-2） gene expression in myocardium in septic rats and evaluate the relationship of the gene expression between TLR4/MD-2 and TNF-α. Methods Sepsis was replicated by intraperitonesl injection of LPS （5 mg/kg）. Forty Wistar rats were randomly divided into normal controls （n = 10）, LPS 1 h, 2 h, 6 h groups （ n = 10, respectively）. Rats were sacrificed at different time points. The gene expression of tissue TLR4/MD-2 and TNF-α in myocardium was measured by semi-quantitative reverse transcription polymerase chain reaction （RT-PCR）. Results TLR4/MD-2 mRNA and TNF-α mRNA could be detected in myocardium with very low values in normal controls, but they were markedly up-regulated and peaked at 2 h, and down-regulated at 6 h. The expression of TLR4/MD-2 mRNA had a positive correlation with TNF-α mRNA in myocardium. Conclusion LPS could up-regulate the expression of TLR4/MD-2 mRNA in myocardium. TLR4 recognizes LPS by the coreceptor-TLR4/MD-2 complex, and MD-2 is a key regulatory molecule in sepsis.